Section 7.2
Using the Law of Universal Gravitation
Practice Test
1.
A satellite orbits Earth 375 km above its surface. What is its speed in orbit?
a.
7.68 × 10
3
m/s
b.
7.61 × 10
3
m/s
c.
7.61 × 10
3
m/s
2
d.
7.68 × 10
3
m/s
2
Hint
2.
If the satellite in Figure 7-10 were to remain above the same point on Earth, what would its orbital radius have to be changed to?
a.
2.2×10
11
m
b.
1.7×10
11
m
c.
1.1×10
11
m
d.
1.3×10
11
m
Hint
3.
A satellite orbits Earth 5.00×10
2
km above its surface. What is its period?
a.
94.6 h
b.
15.7 h
c.
1.43 h
d.
1.58 h
Hint
4.
When Uranus was discovered, why didn't Newton's law of gravitation correctly predict its orbit?
a.
Newton's law of gravitation applies only to objects on Earth.
b.
The period of Uranus was not known at the time.
c.
Uranus was being attracted by the planet Neptune.
d.
Newton's law could not be applied over such great distances.
Hint
5.
If you weigh 500.0 N on Earth's surface, how much would you weigh on the planet Jupiter? Jupiter has a mass of 1.90×10
27
kg and a radius of 71.5×10
6
m.
a.
1.24×10
4
N
b.
1270 N
c.
126 N
d.
1.26 N
Hint
6.
A satellite orbits Earth 375 km above its surface. What is its period?
a.
16.0 h
b.
1.54 h
c.
92.1 h
d.
55.3 h
Hint
7.
If Earth began to shrink but its mass remained the same, what would happen to the value of
g
on Earth's surface?
a.
It would be halved.
b.
It would decrease.
c.
It would increase.
d.
It would remain constant.
Hint
8.
A satellite orbits Earth 5.00×10
2
km above its surface. What is its speed in orbit?
a.
7.61×10
3
m/s
b.
7.90×10
3
m/s
c.
5.92×10
3
m/s
d.
7.76×10
3
m/s
Hint
9.
If you weigh 440.0 N on Earth's surface, how much would you weigh on the planet Mars? Mars has a mass of 6.42×10
23
kg and a radius of 3.40×10
6
m.
a.
235 N
b.
557 N
c.
165 N
d.
1.4×10
3
N
Hint
10.
The __________ of an object is measured by applying a force to the object and measuring its acceleration.
a.
inertial mass
b.
resistance
c.
gravitational mass
d.
weight
Hint
11.
What is the orbital period for the satellite pictured in Figure 7-10?
a.
3.1 h
b.
1.6 h
c.
170 h
d.
0.052 h
Hint
